Truck hoist

Abstract

A hoist for raising and lowering a truck bed to and from a truck frame is provided which utilizes a lever to accomplish initial lift and to further position the hydraulic cylinder at a more efficient angle for completion of the lift process. The hoist further provides a locking device to immobilize the lever and one end of the hydraulic cylinder during certain phases of the raising and lowering cycle, improving safety and stability in the dump bed raising and lowering process.

Description

This invention relates to new and improved hoists useful for raising or lowering the dump bed of a truck. More particularly, this invention relates to underbody hoists which provide substantially improved lifting efficiency of the hydraulic cylinder and optionally provide a mechanism for locking the cylinder in place to provide greater stability when the dump bed is elevated during the dumping operation.Many types of hydraulic hoists have been developed over the years which are particularly useful as underbody hoists for raising and lowering a dump bed, such as the dump bed of a heavy duty dump truck or trailer. Generally speaking, these hoists employ hydraulic cylinders which, when activated, pivot the dump bed about its rear pivots connected to the frame of the truck chassis.In a typical hydraulic truck hoist, a hydraulic cylinder lies lengthwise between the framerails of the vehicle and underneath the truck bed. As the hoist's cylinder extends, one end pushes against the undersid...

AI Technical Summary

Benefits of technology

Generally speaking, this invention fulfills the above-described needs in the art by providing a hoist for raising or lowering a truck bed to and from a truck frame which is capable of being located between the bed and the frame, the hoist comprising: an extendible and retractable cylinder connected at one end to a lever mechanism and at the other end connectable to the underside of a bed, the lever mechanism comprising at least a first pivot, a first pivot centerline, a second pivot, and an elongated arm, the first pivot being attachable to a truck frame and the second pivot being rotatably attached to the cylinder, the second pivot being located at a first offset distance from the centerline of the first pivot, and being rotatable about the first pivot when the cylinder is extended or retracted, the elongated arm being pivota

Problems solved by technology

Due to this inefficiency, large cylinders are required to provide the substantial forces necessary to achieve this initial lift.

However, the cylinder in such devices usually must have a rather long stroke to achieve a sufficient dump angle.

For the most part, they often require large and expensive cylinders.

Many are difficult to install or manufacture.

Other designs are subject to large stresses, are potentially unstable when elevated, or do not achieve superior initial lift.

Stability problems have been known to occur, for example, when wet loads are carried and the entire load is not eliminated during the dumping operation, leaving, for example, some of the load in the most elevated part of the dump bed.

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